In recent years, the potential has escalated for the use of micromechanical elements in a variety of technical arenas such as semiconductor devices. Typically the micromechanical elements are integrated into semiconductor devices, and are housed in cavities or voids formed upon or within, for example, a complimentary metal oxide semiconductor (CMOS) device. While integrating the micromechanical element onto the CMOS substrate, it is equally important to provide adequate environmental protection for the micromechanical elements, and provide electrical connection to the upper layers of the circuit.
The micromechanical element could be moveable or non-moveable, for example, a charge transfer device movable between electrodes or a microfuse element which blows on the application of a suitable current. One of the principal concerns facing the micro-electromechanical systems (MEMS) industry is that the micromechanical elements are highly sensitive to their operational environments which include thermal, chemical and mechanical exposure which may be detrimental to the performance of the semiconductor device. Hence, it is desirable to provide such micromechanical elements with some form of protective seal or seals.
The device incorporating the micromechanical element may equally become damaged, for example, while being handled during subsequent packaging steps or to provide electrical connection to the upper circuit; hence, the need for suitable protection.
It can be appreciated that micromechanical elements require stringent measures of protection, therefore, it is an object of the present invention to provide reliable an enclosure for the micromechanical element in the form of hermetic seals, without increasing the size and cost of the devices. It can be seen therefore, that there is a need to fabricate reliable micromechanical elements for use in semiconductor devices.